1. Field of the Invention
The present invention relates generally to a fiber optic connector having a single connector element for providing both optical fiber alignment and strain relief, and more specifically, to a mechanical splice connector including a splice component operable for aligning and retaining the stub optical fiber and the adjoining field optical fiber, as well as strain relieving the field optical fiber.
2. Technical Background
A key objective contributing to the proper function of a fiber optic mechanical splice connector is the alignment of the mating optical fibers within the connector. Alignment is typically accomplished by applying a biasing force to a splice component to accurately align the stub optical fiber of the connector with the mating field optical fiber. Conventional mechanical splice connectors typically include a pair of opposed splice components, wherein at least one of the splice components defines a recess, channel, groove or the like, for receiving the bare glass portions of the optical fibers. The stub optical fiber and the field optical fiber are aligned and retained between the opposing splice components as the splice components are biased together by an actuator. The splice components are typically disposed within a connector housing, and generally within a ferrule holder secured to the rear of a ferrule mounted upon the stub optical fiber. A projection, such as a rib, keel or the like, extends outwardly from one of the splice components through a passageway in the ferrule holder. The actuator, for example a cam member having an internal geometry defining a cam surface, is positioned over the splice components. In an un-actuated (also referred to as “un-cammed” or “open”) position, a larger internal diameter of the cam surface is located adjacent the projection with only minimal or no interference with the splice component. As the cam member is moved to the actuated (also referred to as “cammed” or “closed”) position, a smaller internal diameter of the cam surface engages and exerts a radial compressive force on the projection, thus biasing the splice components together and thereby aligning and retaining the stub optical fiber and the field optical fiber between the splice components.
Once the optical fibers are aligned and retained in optical continuity, the field optical fiber must be strain relieved to the connector. Strain relief is typically accomplished by crimping a lead-in tube or an annular crimp ring about the buffered portion of the field fiber. As used herein, the terms “buffered” and “buffered optical fiber” each refer to both tight-buffered optical fiber and jacketed, or loose-tube, optical fiber cable having an outer diameter greater than about 250 microns. In contrast, the terms “un-buffered,” “coated” and “coated optical fiber” each refer to the optical fiber as formed in a standard extrusion manufacturing process, including the core, the cladding and an extruded coating having an outer diameter up to and including about 250 microns. A 250 micron diameter un-buffered (hereinafter “coated”) optical fiber is typically upsized to a 900 micron diameter buffered optical fiber or cable for mechanical strain relief and strength purposes. It should be noted that in some instances the coated portion of the field optical fiber may have an outer diameter up to and including about 500 microns. For purposes of simplicity and clarity, however, the outer diameter of the coated portion of the field optical fibers shown and described herein is less than or equal to about 250 microns as obtained in a typical extrusion manufacturing process. A drawback to the conventional strain relief technique for mechanical splice connectors is that once the field optical fiber is strain relieved, the splice cannot be reversed and reworked without destroying the connector assembly and potentially damaging the field optical fiber. Alternative designs for fiber optic mechanical splice connectors are known. For example, U.S. Pat. No. 6,439,780 (the '780 patent) describes a field-installable fiber optic ribbon connector and installation tool. The '780 patent describes a ribbonized portion of the fiber optic ribbon cable being inserted into a flexible portion of a splice component, but does not describe using the splice components as a mechanism to provide strain relief. Furthermore, there is no direct clamping pressure or biasing force exerted over the ribbonized portion by the splice component. U.S. Pat. No. 6,078,719 (the '719 patent) describes an optical fiber holder that clamps and retains both the bare glass portion and the buffered portion of the field optical fiber, but does not align the optical fibers for mechanical splicing. A significant drawback to these other mechanical splice connectors is that optical fiber alignment and strain relief must be performed in more than one step and using more than one element of the connector, thus requiring additional materials, as well as additional time and labor cost to install the connector. A further drawback to these conventional mechanical splice connectors is that once the optical fibers are strain relieved by applying a crimp, the splice cannot be reversed without destroying the connector assembly or potentially damaging the field optical fiber.
Accordingly, what is desired in a fiber optic mechanical splice connector is a single connector element that performs both the function of optical fiber alignment for splicing the stub optical fiber and the field optical fiber, and the function of strain relieving the field optical fiber to the connector. In contrast to conventional fiber optic connectors that include separate connector elements for optical fiber alignment and strain relief, it would be desirable to provide a fiber optic connector having a single connector element that performs both functions in order to save materials, as well as time and labor cost in connector installation. Further, it would be desirable to provide a single connector element for optical fiber alignment and field fiber strain relief that is completely reversible without destroying the connector assembly or potentially damaging the field optical fiber. It would also be desirable to provide a cam assembly, that when rotated or moved to an actuated position, biases the splice components of the connector together, thus closing the splice components around the bare glass portions of the optical fibers and a coated portion, or alternatively, a buffered portion of at least one of the optical fibers.